Method of cleaning wells



June 9; 1931. K. B. BowMAN METHOD OF CLEANING WELLS 'Filed Mrch 7,

Patented June 9,- 1931 f 1,809,546

UNITED STATESl PATENT OFFICE KIEL anowMAN, or MAssILLoN, omo, AssIGNon To THE omo DRILLING COMPANY, or MAssILLoN, omo, A CORPORATION or oHIo METHOD F CLEANING WELLS Application led March 7, 1929. Serial No. 345,043.

The' invention relates to the cleaning of manner illustrated in the accompanying wells and more particularly to an acid treatdrawings, in which i ment for removing incrusting solids from Figure 1 is a longitudinal sectlonal view Water wells. through a well, showing the manner of in- 5. In certain localities the water contains bitroducing the acid at dilferent levels; 55 carbonates of calcium, iron and magnesium, Fig. 2, a similar view showing the manner which are normally soluble in water under of introducing air into the solution; and

pressure, but which are crystallized out upon Fig. 3, la similar view showing the manner the nearest surface if the pressure is released of umping out the acid and water.

or the solution heated. imilar numerals refer to similar. parts 60 These incrusting solids forming upon'thel throughout the drawings.

casings of water wells considerably decrease A well casing is represented at 10, provided the amount of their production, 'and in a with the usual apertures 11 for permitting a comparatively short time the iow may be enflow of water therethrough to the interior tirely stopped, as the formation completely of the casing. 65 covers the perforations in the well casing. In Fig. 1 these apertures are shown as sub- When a well has reached this condition it stantially entirely closed with incrusting solis useless and unless these incrustin solids ids indicated at 12. When a well gets into can be removed from the casing su ciently this condition, it is substantially useless as to uncover the apertures therein, it is necesvery little, if any, water can be obtained 70 sary to abandon the well and drill a new therefrom.

one. f A typical analysis of these incrusting solids The object of the present improvement is is as follows:

tained by introducing into theD well muriatic acid to an amount substantially fty per i These carbonates are. soluble in a lsolution S0 Cent 0f the total Volume 0f Water in the which gives hydrogen ions, such as the acids y We11 In Order t0 evenly distllhute J0he amd and acid salts. A reaction will take place at throughout the well,portions of the acid may Ordinary temperatures and atmospheric be IltIOdUCef 'et dfefent levelepressure, giving an evolution of carbonio AT1 ail' lille S then inserted inte the Wehl Vacid-gas andy salts of the metalsremaining 85 prol'ded With Perfofatiohs l'Jhohghohh the; either suspended or actually dissolved in the depth 0f the Water 1h the Wen aha alf .1S liquid. If pressure is increased, then the reforced into the same. Thesolution 1s allowed action takes place Very S1OW1y and reaches to act for about twenty-four hours and then e,quiiibriuiii very .quickly The Carbonates 40 pumped out and the'iwaber 1S then commu" will not dissolve and the reaction stops. 90 Ously Pumped from the Wen for a perlodpf This is explained by the following typical about twenty-four hours, at the end of which reaction equation. all tracesof the muriatic acid will be gone.

It has been found that this method of l0a0O3 plus 2H01=0a0l2 plus H2003 cleaningwells dissolves and' removes all of CaCO3X2HC1 K1 y 95 the incrusting solids from the casing of the well, entirely uncovering the apertures therev through and permitting a maximum flow of water through the casing.

08.012 X H2003 K2 Where AK1 and K2 are reaction constants, if K1 equals K2, then there will be no reaction.

v The inventlon may be carried out-in the IfK1 is greater than K2, then .the carbonate 100 alsv will dissolve to completion. We can make K11 greater than K2 by removing the H2003 as rapidly as it is formed in the reaction. This can be done by putting agas into the solution and displacing the CO2 as the folf lowing typical reaction:

H2003 plus air=H2O plus C()2 Then the total expression is thus:

and K3 will always be greater than K4. By the use of air or other gases included in the claims the CO2 is taken out of the system by blowing it up out of thewell. The reaction will take place under a pressure which is never exceeded in ordinary water wells.

In carrying out the improved method to which the invention pertains, the first step consists in introducing muriatic acid (28% HC1) below the water level 13of the well. Preferably an amount of muriatic acid estimated at fifty per cent of the total volume of water in the well is introduced at different levels below the water level.

This acid may be introduced into the well by means of a pi e 14 which ispreferably rst lowered to tlie position shown in full lines in Fig. 1, terminating about twenty feet from the bottom of the well as indicated at 15 and one-fourth of the total acid is poured into the well atthis point.

The pipe 14 may then be raised to about one-half the depth of the water, as indicated in broken lines at 15a and another fourth of the acid is added. The pipe may then be raised to about one-fourth the depth of the water, as indicated in broken lines at 15b, and another fourth of the acid introduced, after which the pipe is raised to about ten feet below the water level, as indicated in broken lines at 15e and the remaining fourth of the acid is put into the water.

The next step in the method is illustrated in Fig. 2. The pipe 14 has been withdrawn and an air line 16, provided with spaced apertures 17, extending throughout the entire depth of the water, is inserted to the bottom of the well, as shown.

The apertures 17 are so spaced and cover such an area that air may be forced into the well solution at all depths. Air is turned into the air line 17 and the solution is allowed to act for twenty-four hours.

The air line is then removed and the solution is pumped out by any suitable apparatus indicated generally at 18 in Fig. 3. The Water is pumped out for about twenty-four hours, at the end of which time no trace of the acid remains.

As indicated in Fig. 3, all of the incrusting solids have been dissolved and removed from the casing, leaving the apertures l1 enthe dissolving of the carbonate incrustments v is driven ofi'.

It has been found by actual trial that by merely putting acid into a well the incrustments are not dissolved and that the acid solution does not continue to act beyond a very brief period, and soo-n becomes dormant.

It has also been found by trial that the mere mechanical agitation as by means of a plunger or a propeller mixer does not increase the activity of the acid, over a quiet solution; but that when a gas is forced into theliquid, so as tobubble up through the entire column of liquid in the well, for a substantial period of say twenty-four hours, the carbon dioxide gas formed by the reaction of the acid upon' the incrustments is displaced and carried upward, out from the solution in the well.

As a result of the continual removal of the carbon dioxide gas, the action of the acid continues to be effective without being suppressed bythe presence of the carbon dioxide gas.

I claim:

1. The process of removing incrusting solids from water wells which includes introducing an acid into the water, forcing gas under pressure into and through the solution for about twenty-four hours to drive olf carbon dioxide formed by the action of the acid upon the incrusting solids, and then pumping the solution out of the well.

.. 2. The process of removing incrusting solids from water wells which includes introducing muriatic acid into the water, forcing gas under pressure into and through the solution for about twenty-four hours to drive ofi carbon dioxide formed by the action of the acid upon the incrusting solids, and then pumping the solution out of the well.

3. The process of removing incrusting solids from water wells which includes introducing acid into the water to an amount of fifty per cent of the volume thereof, forcing gas under pressure into and through the solution for about twenty-four hours to drive off carbon dioxide formed by the action of the acid upon the incrusting solids, and then pumping the solution out of the. Well.

4. The process of removing incrusting. solids from water wells which includes introducing muriatic acid into the water to an amount of fifty per cent of the volume thereof, forcing gas under pressure into and through the solution-for about twenty-four hours to drive olf carbon dioxideformed by i the Well. v

9. In a process of removing incrusting the action of the acid upon the incrustingsolids, and then pumpingthe solution out of the Well.

5. The process of removing incrusting solids from water Wells v'vhich includes the introduction of acid at different levels under the Water in the Well. forcing gas under pressure into and through the solution for about twenty-four hours to drive oil' carbon dioxide formed by the action of the acid upon the incrusting solids, and then pumping the solution out of the Well.

6. In a process of removing incrusting solids from Water Wells which includes introducing an acid reacting materialinto the water of the Well, the step of bubbling a gas through the acid solution in the Well.

7. In a process of removing incrusting solids Jfrom Water Wells which includes introducing an acid reacting material into the Water of the Well, the step of removing the carbon dioxide formed by passing a stream of a gas through theacid solution in the Well.

8. In a process sa removing incrusting solids from Water Wells, the nsteps of introducing an acid reacting material into the Water of the Well, disturbing the equilibrium reaction between the acid material and the incrusting material by passing a stream of a gas through the acid solution in the Well until I substantially complete reaction has taken place and removing the acid solution from solids from Water Wells Which includes introducing an acid into the Water of the Well, the step of bubbling air through the acid solution in the Well.

10. In a process of removing incrusting solids from Water Wells which includes introducing an acid into the Water of the Well, the step of removing the carbon dioxide formed by passing air through the acid solution in the well.

11. In a process of removing incrusting solids from Water wells, the steps of introducing. an acid into the Water in the Well, bubbling air through the acid solution in the well until substantially complete reaction be'- tween the acid and the incrusting material has taken place and removing the acid solution from the Well.

12. In a process of removing incrusting solids from Water Wells, the steps of introducing hydrochloric acid into the water in the Well, bubbling air through the acid solution until' substantially complete reaction between the acid and the incrusting material has taken place and removing the acid from the Well.

In testimony that I claim the above, I have hereunto subscribed my name.

KIEL B. BOWMAN. 

